Gear pump



Jan. 12, 1954 LAUCK 2,665,638

GEAR PUMP Filed Oct. 21. 1949 fnunfor'" 0/172, Q:

Patented Jan. 12, 1954 GEAR PUMP John A. Lauck, Shaker Heights, Ohio,assignor to Borg-Warner Corporation, Chicago, 111., a corporation ofIllinois Application October 21, 1949, Serial No. 122,786

8 Claims.

This invention relates to driving mechanisms,

and more particularly to a shaft driving armay seize and shear withoutdisrupting the oper- ;ation of the remaining gears.

It is sometimes desirable to mount a plural "ity of driving elements ona single shaft for rotation therewith. Thus, for example, in certalnuses, particularly in aircraft installations, it has been found that itis desirable to provide standby pumping equipment arranged to becomeimimediately effective upon failure of the primary P p- -mounting thedriving gears of each pump on -a common shaft, as shown in my co-pendingapplication Serial No. 746,584, filed May 7, 194.7. In certain highlycritical uses, it may even be necessary to provide stand-by equipmentfor the :stand-by equipment. Thus, there may be a primary fuel pump, afirst emergency fuel pump and a second emergency fuel pump. pressureloadable pumps are employed, it is quite :feasible to mount the drivinggears of all such pumps on a single shaft and to select the operatingpump merely by causing that pump to become pressure loaded and relievingthe loading pressures on the remaining pumps. Where .a plurality of suchpumps are mounted on a 1- single shaft, it is, however, necessary toprovide Lsome means whereby in the event of seizure of one or more ofthe pumps, the remaining pumps .can continue to operate.

Such an arrangement may include Where An object of the present inventionis to provide a new and improved driving mechanism whereby a pluralityof rotatable elements may be mounted on a common driving shaft and anyone of the rotatable elements permitted to seize -Without disrupting theoperation of the remain- :ing rotatable elements.

In accordance with one embodiment of this finvention as applied to theproblem of driving a plurality of sets of tandem gear pumps havingztheir driving gears mounted on and rotatable 'by :a common quill shaft,each gear has inte ,grally formed therewith one hollow journal memberpartially splined on the inner side thereof, whereby the respectivegears are keyed to suitably located splined portions of the quill shaft.Each splined gear journal member has an annular peripheral shearinggroove formed therein and so located with respect to the splined portionof the journal and the corresponding splined portion of the quill shaftthat any one of the gears may seize and the driving connection betweenthat gear and the shaft will shear,

thereby permitting continued operation of the remaining gears.

Other objects and advantages of the present invention will be apparentfrom the following detailed description taken in conjunction with thedrawings, wherein the single figure is a fra mentary, axial, sectionalview of a plural unit tandem gear pump incorporating a drivingarrangement in accordance with this invention.

Referring now to the drawing, a gear pump housing I is there illustratedenclosing three sets of tandem connected intermeshing gear pumpsdesignated 2, 3 and 4. Each of these gear pumps in the embodimentillustrated is substantially identical to the others and consequentlyonly the gear pump 2 will be described in detail.

The gear pump 2 is of the pressure loaded type, the same being morefully described in United States Patent No. 2,420,622 to Roth et al.,whereby by controlling the pressure loading of the pressure loadablebushings, the pump may be caused to become effective or to becomeineffective. More specifically, the pump 2 comprises a driving gear 6having hollow journal members 1 and 8 extending respectively from theright and left sides thereof and integrally formed therewith. Thedriving gear 6 is splined to the quill shaft 5 for rotation therewith byaxially extending splines 9 formed adjacent the left end portion ofjournal member 8. The splines 9 engage only the right end portion of afirst splined portion H) of the quill shaft 5.

The driving gear 6 and journal members 1 and 8 are supported in flangedbushings l2 and I3, mounted on the right and left sides thereof,respectively, the assembly being located in a first pump gear andbushing receiving bore l4 formed in the housing 1. Either of thebushings may be made axially movable, and in the drawing the leftbushing 13 has been made axially movable and means (not shown) areprovided for communicating discharge pressure to the rear or motivesurfaces of this movable bushing to move said bushing into sealingrelation with the adjacent side surfaces of the driving gear 6. This isexplained in detail in the aforementioned patent to Roth et al. Means(not shown) may also be provided for relieving the loading pressure onthe movable bushings to cause unloading of the pump.

The driving gear 6 meshes with a driven gear l5 disposed in a secondbore l5 formed in the housing I adjacent the bore l4 and having its axisextending parallel thereto. Gear I5 is rotatably supported by a fixedright bushing 11 and an axially movable left bushing I8, the leftbushing [B being pressure loadable and unloadable in the same manner andby the same means as the bushing [3.

It will be noted that an annular groove 20 is formed about the peripheryof the left journal vided by the splined portion 9.

aeeaecs member 8 at a point so located that the groove is positionedimmediately to the right of the internally 'splined iportion t notedthat the right end of the internally splined portion 9 substantiallycoincides with the right end of the peripherally splined portion of theshaft 5. The shaft to the right of the splin'ed portion Hlis reduced indiameter for substantially the length of the gear 6 and associatedjournal members and does not contact the same at any point exceptsplines iii, the gear 6 and associated journals being supported bybushings i2 and i3. Thus, the sole engagement-between the quill shaft 5and the driving gear 6 is pro- In the event that the driving gea'r'fi orthe driven gear !5 should "seizefthen the shear section defined by theannular groove 2i! would shear, thereby interrupt- ,ing'or breaking theconnection between the driving gear'B and the quill shaft 5. The quillshaft mayithen continue to rotate unaffected by the breakdown ofpump 2.

Each of the remaining pumps 3 and 4 are similarly splined to thequill'shaft 5. Thus, the

.pump'set'designated 3 has a splined portion'Ba integrally formed withthe inner side of left journal member 8a and this splinedportion 9aengages a splined portion 28 formed on the periphery of the quill shaft5, the splined portion 22 beginning immediately before the terminationof the right journal member '5 of the driving gear 6- and extending intothe left journal member 8a of the driving gear 6a of the pump set 3.Beyond the splined portion, 2 i, the cross sectional dimension of quillshaft 5 is again reduced as in pump set -2. Annular groove is formedabout the periphery of left journal member 3a immediately to the rightof the termination of the splined section 9a and provides a shearsection.

The pump set A is similarl provided with a shear section'by an annulargroove 28b formed about the periphery of left journal member 8b, thejournal member to being-provided with an internally;splined portion anadapted to engage athird splined portion 23 formed about the pe-'riphery of the quill shaft 5 and extending into splin'edgportion'sb.More pump sets or gears may be employed as required. On the last pump-:set it isnotnecessary to reduce the cross section of'the portion ofquill shaft 5 tothe right of the last splined portion and the rightportion of the; quill shaft may be journalled in the journal -memberslband 8b to maintain the alignment of shaft 5 with respect to the pumpsets.

From the foregoing it will be apparent that while all of the pump setsmay be initially driven =bythe quill shaft 5, and the pump sets havingpressure loading applied to their pressure loadable bushings renderedeffective, upon seizure or "sufficient resistance to rotation occurringat any of the, pump sets, the shear section provided by the annulargroove in the journal member associated with the driving gear of theseized pump Such shearing does not affect connections may shearindependently of the others.

.As an alternative measure, the extreme right #pump set 4 may beprovided with a differently arranged shear section. Thus, an annulargroove 24 may be formed about the periphery of the or the sectionweakened as by the radially ex- It will be further.v

mined resistance being encountered, as by seicure, in the pump set l,the shear section will part. When this alternative shearsectionisprovided, it is unnecessary to provide the shear section defined by theright groove 2%.

While this invention has been described primarily in conjunction with aplurality of gear pumps, it will'be'understood that this use is onlyexemplary and that the present invention is equally applicable to anysituation wherein a plurality of driving-elements are to be rotated byand mounted on a common shaft. Furthermore, it will be apparent thatwhile only three sets of driving elements have been illustrated, thereis, except for practical limitations, no limitation on the number ofdriving elements and shear sections which could be 'so provided.

Where herein the various parts of this invention have been referred toas being located in 1a right or a left position, it will be understoodthat this is done solely for the purpose of-facilitating description andthat such references relate only to the relative positions of the partsas shown in the accompanying drawings.

While but one embodiment of this invention has been shown and described,it will be apparent that many changes and modifications 'maybe madetherein without departing from-the -spirit or scope of thepresentinvention.

What is claimed is:

l. A driving mechanism including. an elongated quill shaft, a pluralityof rotatable elements mounted on said quill shaft in axiallyspacedrelation, each of said-rotatable elements having a journal memberassociated therewith and fixed thereto, each of said journal membershavingan internally splined portion, a plurality of "peripherally'splined portions formed on'said quill shaft andlocated so as to'beengaged'bythe splined portions of'said journal members toform drivingconnections therewith, and eachiof said journal membershaving a shearsectionformed therein and located between'the' driving connection andthe rotatable element whereby upon: occurrence'of a predeterminedexcessive torque on a particular rotatable element, the shear section vof its associated journal member will shear, thereby separating thespline'd portion of-"said journal shaft and located so as to beengaged-bythe splined portions of said I journal members, -f-and each ofsaidjournal membershaving a shear section formed therein whereby uponoccurrence of a "predetermined excessivetorque on "a; "parti'cularrotatable element; the shear's ection-of its associated 'journal member*willshear, "thereby separating the splined portion of said journalmember from the rotatable element; each-ofsaid shear sections"comprising "an annular groove formed in each said journal member andlocated between therotatable element and-the splined portion ofsaid-journal member. Y

3. A driving mechanism for rotating-a plurality of rotatable-elementsmounted on acomm on "drive shaft'inaxially spaced relationand-permitting any one or more of said-"elements to cease rotatingwithout interrupting the rotation of the remaining elements, saidmechanism comprising a plurality of driving portions, one of saiddriving portions associated with each of said elements and connectedthereto by a weakened shear section located between said driving portionand its associated element, each of said driving portions being drivablyconnected to said common drive shaft, said shear sections allowing arotatable element to shear from its associated driving portion uponoccurrence of excessive torque on that particular rotatable element sothat said common drive shaft may continue to drive the remainingrotatable elements.

4. A driving mechanism for rotating a plurality of rotatable elementssupported on a common shaft and permitting cessation of rotation of anyone or more of the rotatable elements without cessation of rotation ofthe other rotatable elements or cessation of rotation of the commondriving shaft, said driving mechanism comprising a plurality of meansdefining shear sections of reduced cross section, one of said shearsection, associated with each of said rotatable elements, and a shaftcoupling for each rotatable element connected to said shaft for rotationtherewith and connected to each rotatable element through said shearsection for rotation of said element, said shear sections being locatedbetween said shaft coupling and said rotatable element.

5. An intermeshing gear type pump assembly including means defining anenclosing housing having a first intermeshing gear pump unit arranged tonormally function as a primary liquid transfer pump, a secondintermeshing gear pump arranged to function normally as a firstemergency liquid transfer pump, and a third intermeshing gear pumparranged to function as a second emergency liquid transfer pump, each ofsaid pumps including a driving gear and a driven gear, means forcontinuously driving the three said pumps and adapted to be connected toa suitable source of power, means for connecting the driving gears ofeach of said pumps to said continuous driving means, said connectingmeans including an independent shear section and a splined portion foreach pump, said shear section including a reduced cross section locatedbetween the driving gear of its associated pump and the splined portionand being arranged to shear in response to the occurrence of apredetermined excessive shearing force from a resistance to turning bythe corresponding one of said pumps to thus produce shearing of theparticular shear portion associated with said pump, and upon occurrenceof the shearing of one or more of said shear sections said driving meansis effective to drive the remaining pumps through the other shearsections.

6. An intermeshing gear type pump assembly including means defining anenclosing housing having a first intermeshing gear pump unit, a secondintermeshing gear pump unit, and a third intermeshing gear pump unit,each of said gear pump units including a driving gear and a driven gear,a drive shaft connecting the three said pumps in continuous drivingrelation and adapted to be connected to a suitable source of power,means connecting said gear pumps to said drive shaft and including ajournal on the driving gear of each gear pump unit, each of saidjournals including a shear section being defined by an annularperipheral groove, each of said shear sections being arranged to shearin response to the occurrence of a predetermined excessive shearingforce resulting from the resistance to turning by the corresponding oneof said pumps, and each of said shear sections further being effectiveto allow said driving means to continue driving the remaining pumps uponthe occurrence of the shearing of the section associated with itsparticular pump.

7. An intermeshing gear type pump assembly including means defining ahousing having a first intermeshing gear pump unit, a secondintermeshing gear pump unit, and a third intermeshing gear pump unit,eachof said gear pump units including a driving gear and a driven gear,said gear pump units being arranged in spaced relationship, a quillshaft adapted to drive said pumps in unison and including peripheralexternal splined portions, sleeve portions on said intermeshing gears,one of said sleeve portions for each of said driving gears, said sleeveportions including internal splines corresponding to the externalsplines of the quill shaft and adapted to be engaged thereby, saidsleeve portions having a shear section of reduced cross sectional arealocated between said splines and said driving gear so as to allowseparation of said sleeve from its corresponding gear in response to apredetermined excessive shearing force caused by the resistance toturning of its corresponding gear and thus be effective to allow theremaining pumps to be driven in unison.

8. A driving mechanism including an elongated quill shaft, a pluralityof rotatable elements mounted in said quill shaft in axially spacedrelation, each of said rotatable elements having a journal memberassociated therewith and fixed thereto, each of said journal membershaving internally splined portions, a plurality of peripherally splinedportions formed on said quill shaft and located so as to be engaged bythe splined portions of said journal members, said quill shaft betweenthe splined portions thereof being of a diameter less than the internaldiameter of said journal member and rotatable elements whereby the soleengagement of the quill shaft and the rotatable elements is provided bythe splined portions, and each of said journal members having a shearsection formed therein and located between the splined portion and therotatable element whereby upon occurrence of a predetermined excessivetorque on a particular rotatable element, the shear section of itsassociated journal member will shear, thereby separating the splinedportion of said journal member from the rotatable element and allowingsaid quill shaft to rotate clear of the rotatable element and journalmember.

JOHN A. LAUCK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,218,300 Nelson Mar. 6, 1917 1,607,383 Aurand Nov. 16, 19261,629,121 Russell et al. May 17, 1927 1,665,026 Grant Apr. 3, 19282,280,392 Herman et a1 Apr. 21, 1942 2,356,322 Johnson Aug. 22, 19442,361,226 Miner Jr., et al. Oct. 24, 1944 2,487,449 Knudson Nov. 8, 1949FOREIGN PATENTS Number Country Date 579,582 Great Britain Aug. 8, 1946

